Retinoid-related orphan receptors (ROR) are reported to have an important role in numerous biological processes. See, for example, Dussault et al. in Mech. Dev. (1998) vol. 70, 147-153; and Andre et al. in EMBO J. (1998) vol. 17, 3867-3877. Scientific investigations relating to each of retinoid-related orphan receptors RORα, RORβ, and RORγ have been described in the literature. See, for example, Hirose et al. in Biochem. Biophys. Res. Commun. (1994) vol. 205, 1976-1983; Giguere et al. in Genes. Dev. (1994) vol. 8, 538-553; Medvedev et al. in Gene (1996) vol. 181, 199-206; Ortiz et al. in Mol. Endocrinol. (1995) vol. 9, 1679-1691; Wiesenberg et al. in Nucleic Acids Res. (1995) vol. 23, 327-333; Carlberg et al. in Mol. Endocrinol. (1994) vol. 8, 757-770; and Becker-Andre et al. in Biochem. Biophys. Res. Commun. (1993) vol. 194, 1371-1379. Continuing research in this field is spurred by the promise of developing new therapeutic agents to treat medical disorders associated with retinoid-related orphan receptor activity.
RORγ has been reported to be expressed in high concentration in various tissues, such as thymus, kidney, liver, muscle, and certain fat tissue. See, for example, Hirose et al. in Biochem. Biophys. Res. Commun. (1994) vol. 205, 1976-1983; Medvedev et al. in Gene (1996) vol. 181, 199-206; Ortiz et al. in Mol. Endocrinol. (1995) vol. 9, 1679-1691; and He et al. in Immunity (1998) vol. 9, 797-806. Two isoforms of RORγ have been identified and are referred to as γ1 and γ2 (also referred to as RORγt). See, for example, He et al. in Immunity (1998) vol. 9, 797-806. Expression of the γ2 isoform has been reported to appear in, for example, double-positive thymocytes. See, for example, He et al. in Immunity (1998) vol. 9, 797-806; and Villey et al. in Eur. J. Immunol. (1999) vol. 29, 4072-4080. RORγt plays a critical role in regulating differentiation of Th17 cells, a subset of T helper lymphocytes. A number of inflammatory cytokines, such as IL-17, IL-22, and IL-23, are synthesized in Th17 cells. These cytokines are important pathogenic factors for many immune and inflammatory diseases. Compounds capable of modulating RORγt activity are contemplated to provide a therapeutic benefit in the treatment of multiple medical disorders, including immune and inflammatory disorders.
Numerous immune and inflammatory disorders continue to afflict millions of patients worldwide. Significant advances have been made in treating these disorders. However, current therapies do not provide satisfactory results for all patients due to, for example, detrimental side effects or insufficient efficacy. Treatments for immune and inflammatory disorders vary depending on the particular medical disorder, and often involve use of immunosuppressive drugs. Surgery (e.g., splenectomy), plasmapheresis, or radiation can be used in certain instances.
One exemplary immune disorder in need of better therapy is psoriasis. Psoriasis is a T cell-mediated inflammatory disease that affects approximately 2% to 3% of adults and has a substantial adverse impact on the quality of life for patients suffering from this disorder. Plaques resulting from psoriasis can be painful and are visually unappealing. Various therapeutics have been developed in an attempt to treat psoriasis. However, the traditional therapies for psoriasis often have toxic adverse effects.
An exemplary inflammatory disorder in need of better treatment is rheumatoid arthritis. This form of arthritis is characterized by inflammation in the synovial membrane and results in destruction of bone. Numerous therapeutics have been developed in an attempt to treat this disorder. Exemplary therapeutics for treating rheumatoid arthritis include glucocorticoids, methotrexate, hydroxychloroquine, sulfasalazine, and leflunomide. However, current therapies are not effective for all patients. Moreover, some patients develop resistance to current therapies.
Accordingly, a need exists for improved treatments for immune disorders and inflammatory disorders. The present invention addresses this need and provides other related advantages.